Reactivity of antistreptococcus hyperimmune sera with human myocardial tissue.

Antimyocardial antibodies were determined in hyperimmune rabbit sera against group A streptococci. The detection method was indirect immunofluorescence in human myocardial tissue sections. Positively reacting sera were absorbed with group A streptococcus cell walls and cytoplasmic membranes, the objective being to locate the cross-reacting antigen in the streptococcus cell under the given experimental conditions. Cell walls gave the better absorption results. Whether or not the streptococci possessed the Fc-reacting factor was without influence on the absorption result.